Embodiments of the disclosed technology relate to a thin film transistor liquid (TFT) array substrate and manufacturing and repairing methods of the same.
Thin-film-transistor liquid crystal displays (TFT-LCDs) have become the mainstream of the current commercially available LCDs for various advantages including smaller volumes, light weight, lower power consumption and little radiation, and take a dominant role in the flat display market. An advanced-super dimensional switching (AD-SDS) type LCD forms a multi-dimensional electric field with parallel electric fields formed by perimeters of pixel electrodes within a same level and longitudinal electric fields formed by pixel electrodes and common electrodes that are located on different levels, causing all liquid crystal molecules between and on top of the pixel electrodes within the LCD panel to rotate, thereby increasing the efficiency of the liquid crystal materials and improving the transmission rate.
In a conventional technology, an AD-SDS type TFT-LCD array substrate and generally comprises the following layered structure: an first indium-tin oxide (ITO) layer formed over a glass substrate, which is also referred to as a first transparent conductive film; a gate layer formed over the first ITO layer for forming a gate line, a common electrode line, a gate electrode and a common electrode; a first insulating layer formed on the gate layer and covering the whole first ITO layer; a semiconductor layer and a source/drain electrode layer formed above the first insulating layer; a second insulating layer formed on the source/drain layer and covering the whole first insulating layer with a through hole formed in the second insulating layer; a pixel electrode formed on the second insulating layer and connected to a drain electrode in the source/drain electrode layer via the through hole in the second insulating layer; and a second ITO layer formed over the second insulating layer. In this way, the layered structure including the above layers form a gate line, a data line, a common electrode line, a pixel electrode, a common electrode and a thin film transistor (TFT) needed for a pixel unit of a TFT display. The pixel electrode and the common electrode construct a capacitor, and can generate a horizontal electric field after applied a voltage along the plane of the substrate such that LC molecules can be tilted regularly. The TFT acts as a switching element for charging and discharging of the capacitor (liquid crystal capacitor). The gate line provides on-voltage for turning on the switching element, and the data line provides a source signal needed for charging the liquid crystal capacitor for displaying. The common electrode line provides a common voltage for the first ITO layer.
In the conventional array substrate, when a data line has a failure, typical repairing methods includes mainly a laser cutting method, a laser chemical vapor deposition (laser CVD) method, a laser welding method, and the like. With respect to a date line failure open, usually a laser CVD tool is employed to bridge the broken parts by using tungsten powders, and the area around the bridge is processed by laser cutting or scraping of ITO film and the like. Among the repairing technologies for a data line failure open, the bridging method consumes tungsten and may bring about damages to the ITO layer of a pixel during the laser cutting or the scraping of ITO film. As a result, problems exist such as high repairing cost, long repairing time period and disadvantageous influence on adjacent pixels.